Process for producing rubbery polymer particle and process for producing resin composition containing the same

ABSTRACT

A process for efficiently producing an agglomerate resulting from removal of impurities from a water-base latex of rubbery polymer particles or dry Powder thereof and producing a dispersion having rubbery polymer particles dispersed in an organic solvent, and a process for efficiently producing a resin composition of low impurity content, in which the state of dispersion of rubbery polymer particles is excellent, from the above dispersion. In particular, a rubbery polymer particle agglomerate of low impurity content is obtained by first mixing a water-base latex of rubbery polymer particles with an organic solvent exhibiting partial solubility in water, bringing the resultant mixture into contact with water to thereby form a rubbery polymer particle agglomerate, and thereafter separating the water phase from the agglomerate/water phase mixture. Further, a resin composition of low impurity content having rubbe, polymer particles favorably dispersed is obtained by first adding an organic solvent to the above agglomerate, mixing the obtained dispersion with a polymerizable organic compound having a reactive group, such as an epoxy resin, and thereafter distilling off volatile components.

This is a 371 national phase application of PCT/JP2004/013017 filed 1Sep. 2004, claiming priority to Japanese Applications No. 2003-326711filed 18 Sep. 2003, and No. 2004-063696 filed 8 Mar. 2004, the contentsof which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a process for producing refined rubberypolymer particles from an aqueous latex of the rubbery polymerparticles, as well as a process for producing a re-dispersion in whichthe refined rubbery polymer particles are re-dispersed in an organicsolvent.

Further, the invention concerns a process for producing a resincomposition in which rubbery polymer particles such as elastomericmaterial are re-dispersed in a thermosetting resin such as an epoxyresin and it can provide a resin composition with impurities beingdecreased remarkably compared with usual case.

Further, according to a preferred embodiment of the invention, sinceproduction can be carried out at a high efficiency by making stepscontinuous, it can provide a production process reduced in the cost ofequipment.

BACKGROUND ART

Heretofore, in a case of producing a rubbery polymer from an aqueouslatex of rubbery polymer particles, it has been practiced a method of atfirst obtaining a coagulate by various methods and then removing wateror solvent from the coagulate followed by drying.

As a method of obtaining the coagulate, it has been proposed, forexample, (1) a method of adding an inorganic electrolyte or acid as acoagulant, (2) a method of adding a nonionic polymer coagulant), (3) amethod of bringing an organic solvent into direct contact with a latex,(4) a method of heating or freezing a latex, (5) a method of providingmechanical shearing force, or a method of appropriately combining them.

In this case, as a measure for removing an emulsifier and an electrolytederived from the polymer and, further, impurities such as an inorganicelectrolyte used as the coagulant from the obtained coagulate, a methodof bringing the coagulate into contact with water has been adoptedgenerally. However, for removing such impurities, not only a greatamount of water is necessary but also impurities can not be removedsufficiently at present. Further, a method of cleaning by an organicsolvent has also been used, but this complicates the steps to make theprocess industrially disadvantageous.

On the other hand, cured products of polymerizable organic compoundshaving reactive functional groups, for example, cured products of epoxyresins are excellent in various aspects such as dimensional stability,mechanical strength, electric insulation property, heat resistance,water proofness and chemical resistance. However, cured products ofepoxy resins have low fracture toughness to sometimes show extremelybrittleness and such nature often results in problems in wide range ofapplication uses.

As one of methods for solving the problems, it has been attemptedtoblenda rubbery ingredient in an epoxy resin. Among all, a method ofblending a rubbery polymer previously prepared into a particulate shapeby using, for example, a polymerization method in an aqueous mediumtypically represented by emulsion polymerization, re-dispersionpolymerization or suspension polymerization is considered to providevarious advantages compared, for example, with a method of dissolvingand mixing non-crosslinked indefinite rubber ingredient to an epoxyresin and then causing phase separation in the curing process therebyforming a dispersion phase of the rubber ingredient in an epoxy resincured product continuous phase, such that the state of dispersion isless changed depending on the blending and curing conditions, inprinciple, and the rubber ingredient does not intrude to the continuousphase of the epoxy resin cured product by previously crosslinking therubber ingredient thus causing less lowering of the heat resistance andthe rigidity, and various production processes have been proposed.

For example, (6) a method of heating apartially cross linked rubberyrandom copolymer particles prepared by emulsion polymerization using anonionic emulsifier or the like to a temperature higher than a cloudpoint of the emulsifier, thereby coagulating them, then optionallywashing the coagulate with water and mixing the same with an epoxy resin(for example refer to JP Nos. 1708498, 2751071, and JP-A No. 5-295237),(7) a method of mixing a rubbery polymer latex and an epoxy resin andthen evaporating off a water content to obtain a mixture (for example,refer to JP-A No. 6-107910), and (8) a method of mixing a rubberypolymer latex with an epoxy resin under the presence of an organicsolvent to obtain a mixture (for example, refer to the specification ofU.S. Pat. No. 4,778,851) are disclosed.

Since the method (6) described above is a method of obtaining acoagulate by the use of a coagulant, mainly, an inorganic electrolyte,impurities such as an emulsifier which is deposited to the polymer orconfined in the coagulated polymer upon coagulation can not be removedsufficiently while a greater amount of water is used at present.Further, since the rubbery polymer particles are intensely adhered toeach other by coagulation also including coagulation by heating, itrequires pulverization or re-dispersion operation with a considerablelarge mechanical shearing force upon mixing with the epoxy resin, and itis often difficult to uniformly re-disperse the rubbery polymerparticles in the epoxy resin while a larger amount of energy is used.

In the method (7) above, impurities such as emulsifier and electrolytederived from the polymer are left as they are and, in addition, sincethe epoxy resin is only slightly soluble in water, even when aconsiderably large mechanical shearing force is applied, it still leavesa not-yet-mixed portion, and lumpy coagulate are sometimes formed in thenot-mixed portion.

Since the method (8) described above does not include coagulatingoperation, an epoxy resin composition with the rubbery polymer beingre-dispersed uniformly can be obtained easily, but a great amount ofwater content present together with the organic solvent in the system(mixture) (the water content more than the amount which the organicsolvent can solve) has to be separated or evaporated off. However,separation of the organic solvent layer and the aqueous layer requiresmuch time such as one day and one night, or the organic solvent layerand the aqueous layer are difficult to be separated substantially sincethey form a stable emulsified suspension. Further, in a case of removingthe water content by evaporation, a great amount of energy is necessaryand, in addition, water soluble impurities such as an emulsifier orsub-starting materials usually used in the production of rubbery polymerlatexes remain in the composition to degrade the quality as well.Accordingly, removal of the water content is troublesome in any of themethods of separation or removal by evaporation, which can not be saidindustrially preferred.

An object of the present invention is to provide, as a process forproducing rubbery polymer particles refined from an aqueous latex ofrubbery polymer particles, an efficient production process of obtaininga loose flocculate from the rubbery polymer particles obtained in thestate of an aqueous latex without using a coagulant under the presenceof an organic solvent and discharging the impurities to the aqueousphase and, preferably, provide a further efficient production processcapable of reduce the cost of equipment by a continuous processing.Further, it intends to provide a process for producing a resincomposition conveniently and efficiently that can uniformly mix anddisperse rubbery polymer particles in a polymerizable organic compoundhaving a reactive functional group thereby remarkably decreasingimpurities such as an emulsifier or an electrolyte derived from thepolymer particles, by re-dispersing a loose flocculate again in theorganic solvent and mixing the same with the polymerizable organiccompound having the reactive functional group.

DISCLOSURE OF THE INVENTION

The present invention relates to;

-   (1) a process for producing refined rubbery polymer particles (A)    comprising: bringing water (D) into contact with a mixture (C)    obtained by mixing an aqueous latex of the rubbery polymer    particles (A) with an organic solvent (B) exhibiting partial    solubility to water; thereby forming a flocculate (F) of the rubbery    polymer particles (A) containing the organic solvent (B) in an    aqueous phase (E); and then separating the flocculate (F) (Claim 1);-   (2) The process according to claim 1, wherein water (D) is    continuously mixed and brought into contact with the mixture (C)    (claim 2);-   (3) The process according to claim 2, wherein the mixture (C) and    the water (D) are supplied from the bottom of a mixing device and a    mixture of the flocculate (F) and the aqueous phase (E) is recovered    from an upper part of the mixing device (claim 3);-   (4) a process for producing refined rubbery polymer particles (A),    comprising: removing water and/or removing solvent from the    flocculate (F) of the refined rubbery polymer particles (A) obtained    by the process according to any one of claims 1 to 3, followed by    drying (claim 4);-   (5) a process for producing a dispersion (G), comprising: adding an    organic solvent exhibiting an affinity with the rubbery polymer    particles (A) to the flocculate (F) of refined rubbery polymer    particles obtained by the process according to any one of claims 1    to 3; and thereby obtaining the dispersion (G) in which the rubbery    polymer particles (A) are dispersed in the organic solvent (claim    5);-   (6) a process for producing a resin composition in which rubbery    polymer particles (A) dispersed in a polymerizable organic    compound (H) having a reactive functional group, comprising: mixing    the dispersion (G) obtained by the production process according to    claim 5 and the polymerizable organic compound (H) and then removing    the volatile ingredient by evaporation (claim 6),-   (7) a process for producing a resin composition comprising rubbery    polymer particles (A) dispersed in a polymerizable organic    compound (H) having a reactive functional group, comprising: mixing    the flocculate (F) obtained by the process according to anyone of    claims 1 to 3 and the polymerizable organic compound (H); then    removing the volatile ingredient by evaporation (claim 7);-   (8) The process for a resin composition according to claim 6 or 7,    wherein the polymerizable organic compound (H) having the reactive    functional group is an epoxy resin (claim 8);-   (9) The process according to anyone of claims 1 to 8, wherein the    solubility to water at 20° C. of the organic solvent (B) exhibiting    a partial solubility to water is 5% by weight or more and 40% by    weight or less (claim 9);-   (10) The process according to anyone of claims 1 to 9, wherein the    amount of water (D) to be brought into contact with the mixture (C)    obtained by mixing the aqueous latex of the rubbery polymer    particles (A) with the organic solvent (B) exhibiting the partial    solubility to water is 40 parts by weight or more and 350 parts by    weight or less based on 100 parts by weight of the organic    solvent (B) (claim 10);-   (11) The process according to anyone of claims 1 to 10, wherein the    ratio of the organic solvent (B) exhibiting the partial solubility    to water contained in the flocculate (F) is 30% by weight or more    based on the whole weight of the flocculate (F) (claim 11);-   (12) The process according to anyone of claims 1 toll, wherein the    rubbery polymer particles (A) comprise a polymer having a two or    more multi-layered structure and contain at least one layer of    cross-linked rubbery polymer layer (claim 12);-   (13) a process according to any one of claims 1 to 12, wherein the    rubbery polymer particles (A) comprise a graft copolymer having from    5 to 60% by weight of a shell layer (A-2) obtained by polymerizing    at least one vinyl polymerizable monomer selected from (meth)arcylic    ester, aromatic vinyl, vinyl cyanate, unsaturated acid derivative,    (meth)acrylamide derivative and maleimide derivative in the presence    of from 40 to 95% by weight of a rubber particle core (A-1)    comprising a elastmeric material constituted with 50 to 100% by    weight of at least one monomer selected from diene monomers and    (meth)arcylic ester monomers, and 0 to 50% by weight of other    copolymerizable vinyl monomers, polysiloxane elastmeric materials or    a mixture there of (claim 13);-   (14) The process according to claim 13, wherein the shell layer    (A-2) of the rubbery polymer particles (A) has at least one reactive    functional group selected from the group consisting of epoxy group,    carboxylic group, hydroxylic group and carbon-to-carbon double bond    (claim 14);-   (15) a flocculate (F) comprising rubbery polymer particles (A),    organic solvent (B), and water (D) obtained by the process according    to any one of claims 1 to 3 (claim 15);-   (16) rubbery polymer particles obtained by the process according to    any one of claims 1 to 4 (claim 16);-   (17) a dispersion (G) comprising rubbery polymer particles (A), an    organic solvent exhibiting an affinity with the rubbery polymer    particles (A) and water (D), obtained by the production process    according to claim 5 (claim 17);-   (18) a resin composition obtained by the process according to any    one of claims 6 to 14 (claim 18);-   (19) a cured product formed by curing the epoxy resin composition    obtained by the process of any one of claims 8 to 14 (claim 19).

In the process of the invention, an aqueous latex of the rubbery polymerparticles (A) is, at first, mixed with the organic solvent (B)exhibiting the partial solubility to water.

The rubbery polymer particles (A) are not particularly limited but arepreferably polymers having two or more multi-layered structure,particularly, preferably core-shell type polymers, from the view pointthat designing rubber properties is easy and further, resin compositionsby the process of the present invention are easily manufactured. Thecore-shell type polymer is a polymer comprising a rubber particle core(A-1) formed of a polymer comprising an elastomeric or rubbery polymeras a main ingredient and a shell layer (A-2) formed of a polymer graftpolymerized therewith, and it has a feature in that the shell layer(A-2) partially or entirely covers the surface of the rubber particlecore (A-1) by graft polymerizing a monomer constituting the graftingredient to the core.

It is preferred that the polymer constituting the rubber particle core(A-1) is crosslinked and the polymer constituting the rubber particlecore (A-1) can swell to an appropriate solvent but it is notsubstantially dissolved to the solvent. Further, when it is intended tobe dispersed in the epoxy resin, the rubber particles core (A-1) ispreferably insoluble to the epoxy resin and, further, the gel content ofthe rubber particle core (A-1) is 60% by weight or more, morepreferably, 80% by weight or more and, particularly preferably, 90% byweight or more and, most preferably, 95% by weight or more in the rubberparticle core (A-1).

On the other hand, since it can be produced easily by knownpolymerization methods such as emulsion polymerization and it hasfavorable property as the rubber, the polymer constituting the rubberparticle core (A-1) has a glass transition temperature (Tg) of 0° C. orlower and, preferably, −10° C. or lower. With a view point that it isavailable at a reduced cost and that the property of the obtainedpolymer as a rubber is excellent, the polymer constituting the rubberparticle core (A-1) is preferably constituted from elastomeric materialcomprising from 50 to 100% by weight of at least one member selectedfrom diene monomers (conjugated diene monomers) and (meth)arcylic acidester monomer sand 0 to 50% by weight of other copolymerizable vinylmonomers, or polysiloxane type elastomers or a combination of them foruse. In the invention, (meth)acryl means acryl and/or methacryl.

The diene monomer (conjugated diene monomer) constituting theelastomeric material is not limited particularly and can include, forexample, butadiene, isoprene and chloroprene. Among them, butadiene isparticularly preferred because the property of the obtained polymer isexcellent as a rubber. Further, the (meth)acrylic ester monomer is notparticularly limited and includes, for example, butyl acrylate,2-ethylhexyl acrylate and lauryl methacrylate. With a view point thatthe property of the obtained polymer is excellent as a rubber, butylacrylate or 2-ethylhexyl acrylate is particularly preferred. They can beused alone or as a combination of two or more of them.

Further, the above-mentioned elastomeric materials of a diene monomer or(meth)acrylate ester monomer may also be a copolymer of a vinyl monomercopolymerizable therewith. The vinyl monomer copolymerizable with thediene monomer or (meth)arcylic ester monomers can include, for example,aromatic vinyl monomers and vinyl cyanate monomers. As the aromaticvinyl monomers, for example, styrene, α-methylstyrene, vinyl naphthalenecan be used, while as the vinyl cyanate monomers, for example, (meth)acrylonitrile or substituted acrylonitrile may be used. They may be usedalone or as a combination of two or more of them.

The amount of the diene monomer or (meth)arcylic ester monomer to beused is, preferably, 50% by weight or more and, more preferably, 60% byweight or more based on the entire weight of the elastomeric material.In a case where the amount of the diene monomer or (meth)arcylic estermonomer to be used for the entire rubber elastomer is less than50% byweight, the ability of providing the toughness to the cured product ofthe polymerizable organic compound (H) having the reactive functionalgroup, for example, an epoxy group is sometimes deteriorated. On theother hand, the amount of the monomer copolymerizable therewith to beused is, preferably, 50% by weight or less and, more preferably, 40% byweight or less based on the entire weight of the elastmeric material .

Further, as the ingredient constituting the elastmeric material, apolyfuntional monomer may also be contained for controlling the degreeof crosslinking. The polyfunctional monomer can include, for example,divinylbenzene, butanediol di(meth)acrylate, triallyl (iso)cyanurate,allyl(meth)acrylic, diallyl itaconate, and diallyl phthalate. The amountof use thereof is 10% by weight or less, preferably, 5% by weight orless and, further preferably, 3% by weight or less based on the entireweight of the elastomeric material. In a case where the amount of useexceeds 10% by weight, the ability of providing the toughness to thecured product of the polymerizable organic compound (H) having thereactive functional group tends to be deteriorated.

Further, for controlling the molecular weight or the crosslinking degreeof the polymer constituting the elastmeric material, a chain transferagent may be used optionally. The chain transfer agent can include, forexample, an alkylmercaptan containing from 5 to 20 carbon atoms. Theamount of use is 5% by weight or less and, preferably, 3% by weight orless based on the entire weight of the elastmeric material. In a casewhere the amount of use exceeds 5% by weight, since the amount of thenot-crosslinked ingredient in the rubber particle core (A-1) increases,when an epoxy resin composition is prepared, for example, it tends togive undesired effect on the heat resistance, rigidity, etc. of thecomposition.

Further, as the rubber particle core (A-1), a polysiloxane typeelastomer may also be used instead of the elastmeric material describedabove or in combination therewith. In a case of using the polysiloxanetype elastomer as the rubber particle core (A-1), a polysiloxane typeelastomer constituted with dialkyl or diaryl substituted silyloxy unit,for example, dimethyl silyloxy, methylphenyl silyloxy, diphenylsilyloxy, etc. can be used. Further, in a case of using suchpolysiloxane type elastomer, it is more preferred to previouslyintroduce a crosslinking structure by partially using a polyfunctionalalkoxy silane compound together or by radial polymerization of silanecompound having a vinylic reactive group during polymerization.

The shell layer (A-2) can provide the affinity to the rubbery polymerparticles (A) for the dispersion stably in the form of primary particlesin the polymerizable organic compound (H) having the reactive functionalgroup.

The polymer constituting the shell layer (A-2) is graft polymerized withthe polymer constituting the rubber particle core (A-1), preferablyforming a chemical bonding with the polymer constituting the core (A-1)substantially. For facilitating the production of the resin compositionin the production process of the invention, it is preferred that 70% byweight or more, more preferably, 80% by weight or more and, furtherpreferably, 90% by weight or more of the polymer constituting theshell-layer (A-2) is bonded with the core (A-1).

The shell layer (A-2) preferably has swellability, compatibility oraffinity to the organic solvent (B) to be described later and thepolymerizable organic compound (H) having the reactivity group from theviewpoint that the rubbery polymer particles are uniformly mixed anddispersed easily in the polymerizable organic compound (H) having thereactive functional group.

Further, in accordance with the requirement during use, the shell layer(A-2) preferably has a reactivity with the polymerizable organiccompound (H) having the reactive functional group or the curing agentblended upon use and has a capability of reacting and forming chemicalbonding therewith under the reacting and curing conditions where thepolymerizable organic compound (H) having the reactive functional groupreacts with the curing agent.

The polymer constituting the shell layer (A-2) is preferably a polymeror copolymer obtained by polymerizing or copolymerizing one or moreingredient selected from (meth)arcylic esters, aromatic vinyl compounds,vinyl cyanate compounds, unsaturated acid derivatives, (meth)acrylamidederivatives and maleimide derivatives. Particularly, in a case wherechemical reactivity is required for the shell layer (A-2) during curingof the epoxy resin, it is preferred to use a copolymer obtained bycopolymerizing one or more of monomers containing one or more ofreactive functional groups selected, for example, from epoxy group,carboxyl group, hydroxyl group, carbon-carbon double bond, amino groupor amide group which has a reactivity, for example, with thepolymerizable organic compound (H) to be described later, or a curingagent thereof, or a curing catalyst thereof, etc., in addition toalky(meth)arcylic ester, aromatic vinyl compound or vinyl cyanatecompound. Further, the functional group is, more preferably, at leastone reactive functional group selected from the group consisting ofepoxy group, carboxyl group, hydroxyl group, or carbon-carbon doublebond.

As examples of the (meth)arcylic esters, alkyl(meth)acrylate ester suchas methyl(meth)acrylate, ethyl(meth)acrylate, or butyl(meth)acrylate,2-ethylhexyl(meth)acrylate may be mentioned. As examples of the aromaticvinyl compounds, styrene, α-methylstyrene, alkyl-substituted styreneand, further, halogen-substituted styrenes such as bromo styrene, orchloro styrene maybe mentioned. Further, as examples of the vinylcyanate compounds, (meth)acrylonitrile or substituted acrylonitrile maybe mentioned. Further, as examples of the monomers containing thefunctional group having reactivity, 2-hydroxylethyl (meth)acrylate,2-aminoethyl(meth)acrylate or glycidyl(meth)acrylate as (meth)acrylateesters having the reactive side chain may be mentioned. As examples ofthe vinyl ether containing the reactive group, glycidyl vinyl ether orallyl vinyl ether may be mentioned. As examples of the unsaturatedcarboxylic acid derivatives, (meth)acrylic acid, itaconic acid,chrotonic acid and maleic acid anhydride, etc may be mentioned. Asexamples of (meth)acrylamide derivative, (meth)acrylamide (includingN-substituted product) may be mentioned. As examples of the maleimidederivative, maleicacid imide (including N-substitution product) may bementioned.

A preferred rubber particle core (A-1)/shell layer (A-2) ratio (weightratio) of the rubbery polymer particles (A) is within a range of 40/60to 95/5, more preferably, 50/50 to 95/5 and, further preferably, 60/40to 85/15. In a case where the (A-1)/(A-2) ratio is out of 40/60 and theratio of the rubber particle core (A-1) is lowered, the effect ofimproving the toughness for the polymerizable organic compound (H)having the reactivity tends to be lowered. On the other hand, in a casewhere the ratio is out of 95/5 and the shell layer (A-2) ratio islowered, coagulation tends to occur to result in a problem for theoperability during handling in this production process and the expectedproperties may not be obtained.

The rubbery polymer particles (A) can be produced by a well-knownmethod, for example, emulsion polymerization, suspension polymerization,or micro-suspension polymerization. Among them, a production process bythe emulsion polymerization is suitable from the view point that thedesign for the composition of the rubbery polymer particles (A) is easy,the industrial production is easy and the latex of the rubbery polymerparticles suitable to this process can be obtained easily. As theemulsifying or dispersing agent in an aqueous medium, it is preferred touse those not losing the emulsifying or dispersion stability) even in acase where pH of the aqueous latex is made neutral. Specifically, theyinclude, for example, nonionic emulsifier or dispersant such as alkalimetal salts or ammonium salts of various acids, for example, alkyl oraryl sulfonic acids typically represented by dioctyl sulfosuccinic acidor dodecylbenzene sulfonic acid, alkyl or aryl sulfonic acid typicallyrepresented by dodecyl sulfonic acid, alkyl or aryl ether sulfonic acid,alkyl or aryl substituted phosphoric acid, alkyl or aryl ethersubstituted phosphoric acid, or N-alkyl or aryl sarcosinic acidtypically represented by dodecyl sarcosinic acid, alkyl or arylcarboxylic acid typically represented by oleic acid or stearic acid,alkyl or aryl ether carboxylic acids, and alkyl or aryl substitutedpolyethylene glycol, and dispersant such as polyvinyl alcohol, alkylsubstituted cellulose, polyvinyl pyrrolidone or polyacrylic acidderivative. They may be used alone or two or more of them may beproperly combined for use.

In view of the purpose of the invention, the emulsifying or dispersingagent described above is preferably used in a smallest amount tomaintain the required emulsion or dispersion stability during the latexpreparation process of the rubbery polymer particles (A), or it is morepreferred that it is extracted and removed to the aqueous phase (E) tosuch a residual amount as not giving undesired effects on the propertiesof the resin composition produced based on this production method.

The particle size of the rubbery polymer particles (A) usable in theproduction process according to the invention is not particularlylimited and any of those capable of obtaining (A) stably in the state ofthe latex can be used without problem and, with a view point ofindustrial productivity, however, those having a volume average particlesize of 0.03 to 2 μm are more preferred in view of easy production. Thevolume average particle size can be measured, for example, by usingMICROTRACK UPA or MICROTRACK FRA (each manufactured by Nikkiso Co.).

As the organic solvent (B) exhibiting the partial solubility to waterused in the invention, any solvent can be used with no restriction solong as it is at least one or more organic solvents or an organicsolvent mixture capable of attaining mixing of the rubbery polymerparticles (A) and the organic solvent (B) with no substantialcoagulation) and precipitation upon mixing, and it is preferably anorganic solvent having a solubility to water at 20° C. of 5% by weightor more and 40% by weight or less and, more preferably, 5% by weight ormore and 30% by weight or less. In a case where the solubility of theorganic solvent (B) to water at 20° C. exceeds 40% by weight, theaqueous latex of the polymer particles (A) sometimes cause partialcoagulation to result in a trouble in the smooth mixing operation. In acase where the solubility to water is less than 5% by weight, the mixingoperation of the polymer particles (A) with the aqueous latex becomesinsufficient tending to make the smooth mixing difficult.

Specific examples of the organic solvent (B) includes one or moreorganic solvents selected from esters such as methyl acetate, ethylacetate, propyl acetate, and butyl acetate, ketones such as acetone,methyl ethyl ketone, diethyl ketone and methyl isobutyl ketone, alcoholssuch as methanol, (iso)propanol, and butanol, ethers such astetrahydrofuran, tetrahydropyrane, dioxane and diethyl ether, aromatichydrocarbons such as benzene, toluene, and xylene, and halogenatedhydrocarbons such as methylene chloride and chloroform, or a mixturethereof which can satisfy the solubility to water at 20° C. within therange described above. Among them, from a view point of affinity withthe polymerizable organic compound having the reactivity and easyavailability, those containing 50% or more of methyl ethyl ketone arefurther preferred and those containing 75% by weight or more areparticularly preferred.

While the amount of the organic solvent (B) to be used may varydepending on the kind of the rubbery polymer particles (A), or the solidconcentration of the rubbery polymer particles (A) in the aqueous latex,the organic solvent (B) is used in an amount of preferably from 50 to400 parts by weight and, more preferably, from 70 to 300 parts by weightbased on 100 parts by weight of the latex of the rubbery polymerparticles (A). In a case where the amount of the organic solvent (B) isless than 50 parts by weight, the rubbery polymer particles (A) can notsometimes be dispersed stably and viscosity increases tending to makehandling difficult. On the other hand, in a case where it exceeds 400parts by weight, the amount of the organic solvent (B) increases, whichis not economical in view of the substrate removal.

In the mixing operation for the aqueous latex of the rubbery polymerparticles (A) and the organic solvent (B) exhibiting the partialsolubility to water, no special device or method is necessary and anyknown device or method can be used so long as a good mixing state can beobtained. While usual device includes a mixing vessel with an agitator,continuous processing by a static mixer or line mixer (system ofincorporating a mixing device to a part of pipeline) is also possible.

In the invention, the mixture (C) obtained as described above is broughtinto contact with water (D). By the operation, a part of the organicsolvent (B) contained in the mixture (C) is dissolved into water (D) andcan form an aqueous phase (E). At the same time, the water contentderived from the aqueous latex contained in the mixture (C) can also bedrained to the aqueous phase (E). Accordingly, the mixture (C) is in theform where the rubbery polymer particles (A) are concentrated in thewater-containing organic solvent (B) and, as a result, a flocculate (F)is formed.

The operation of forming the flocculate (F) is preferably carried out,from a view point of preventing the occurrence of partialnon-flocculated product, under mixing or under flowing condition capableof providing identical fluidity with that of the mixing. For example, itcan be carried out by batchwise operation or continuous operation in astirring vessel with a stirrer. For the addition method of water (D),for example, a continuous addition method or a collective additionmethod can be applied.

In the invention, for carrying out the operation of forming theflocculate (F) efficiently, it is preferred to continuously supply themixture (C) and water (D) to a device provided with a mixing function,mix and contact them thereby continuously obtaining the flocculate (F)and the aqueous phase (E). The agitator or the shape of the device formixing is not particularly limited but since the flocculate (F)generally has a floating property relative to the aqueous phase (E), itis preferable to adopt a method of supplying the mixture (C) and water(D) from the bottom of the device and extract the flocculate (F) and theaqueous phase (E) from the upper portion of the device. Herein, thebottom part of the device means that it situates at a position of ⅓ orless for the height from the bottom face of the device to the liquidsurface with reference to the bottom, while the upper portion of thedevice means that it situates at a position of ⅓ from the liquid surfaceor higher to the the liquid surface, with reference to the height fromthe bottom face of the device to the liquid surface. By adapting theoperation of forming the flocculate (F) continuously as described above,it is possible to reduce the cost of equipment by the scale-reduction ofthe device and improve the productivity.

While the amount of water (D) added to or brought in to contact with themixture (C) may vary depending on the kind of the rubbery polymerparticles (A), the solid concentration of the rubbery polymer particles(A) in the aqueous latex, and the kind and the amount of the organicsolvent (B), the amount of water (D) is preferably 40 parts by weight ormore and 350 parts by weight or less and, more preferably, 60 parts byweight or more and 250 parts by weight or less based on 100 parts byweight of the organic solvent (B) used upon mixing with the aqueouslatex. In a case where the amount of the water (D) is less than 40 partsby weight, the flocculate (F) of the rubbery polymer particles (A) tendsto be less formed and, on the other hand, in a case where it exceeds 350parts by weight, since the concentration of the organic solvent (B) inthe flocculate (F) formed is lowered, the dispersibility tends to belowered such that it requires a longer time for re-dispersion of theflocculate (F) in the subsequent step.

The flocculating operation and the flocculate (F) formed in theinvention have the following features.

-   (a) Generally, in the coagulating operation by the addition of a    coagulant such as an electrolyte or an acid, or by heating    operation, most of the emulsifier or the electrolyte derived from    the latex of the rubbery polymer particles (A) are often adsorbed to    the surface of the coagulate, or included in the inside of the    coagulate and they can not be removed easily even when washed with    water after coagulation. On the contrary, in the invention, since    the emulsifier and the electrolyte derived from the rubbery polymer    particles (A) are released from the flocculate (F) and then    transferred to the aqueous phase (E) through the operation from the    mixing of the latex of the rubbery polymer particles (A) with the    organic solvent (B) to the flocculation of the rubbery polymer    particles (A), they can be removed easily.-   (b) Generally, coagulate formed by the addition of an electrolyte or    a coagulant such as an acid or by heating operation is a firm    coagulate which is difficult to be re-dispersed from the state of    the coagulate to the state of primary particles of the rubbery    polymer particles (A) even by mechanical shearing. On the other    hand, for the flocculate (F) obtained by the invention, most portion    thereof can be re-dispersed as the primary particles of the rubbery    polymer (A), for example, by subsequent mixing with an organic    solvent exhibiting affinity with the rubbery polymer particles (A)    under mixing. That is, the flocculate (F) obtained in the invention    has a reversibility in the organic solvent with respect to    flocculation and re-dispersion of the particles. This is referred to    as a loose flocculate in the invention.

The reason regarding (b) above has not yet been elucidated sufficientlybut it is considered that the rubbery polymer particles (A) transformreversibly from the state being dispersed as particles in the organicsolvent (B), through the increase of polymer particle concentrationcaused by the elution of the organic solvent (B) into the aqueous phase(E) by adding water (D) into a moderately flocculated state containingthe organic solvent, and as a result, the flocculate (F) is formed.Accordingly, it is considered that particle re-dispersion of the rubberypolymer particles (A) can be reproduced easily by the re-addition of theorganic solvent in the production process of the invention.

Accordingly, by separating the formed flocculate (F) and the aqueousphase (E) containing the organic solvent, it is possible to remove thewater content contained in the organic solvent (B) entrained in theflocculate (F) and obtain refined rubbery polymer particles (A), fromwhich most portion of the emulsifier and the electrolyte derived fromthe rubbery polymer particles (A) is separated and removed together withthe aqueous phase (E).

Separability between the flocculate (F) and the aqueous phase (E) isfavorable, and separation can be carried out by using a usual filtersuch as filter paper, filter cloth or metal screen having relativelycoarse openings. In a case of optionally removing the impurities such asthe emulsifier or the electrolyte remained in the water contententrained in the flocculate (F), it is preferred to repeat the operationof adding water containing the organic solvent (B) and separating theflocculate (F) and the aqueous phase (E).

In a case where it is intended to obtain refined rubbery polymerparticles (A) as a dry powder, this can be obtained by subjecting theflocculate (F) to water removal and/or solvent removal, followed bydrying. In this case, it is preferred to finally wash the flocculate (F)with water not containing the organic solvent (B). This is becauseparticles tend to be agglomerated to each other if the organic solvent(B) is contained in a great amount. As described above, the dry powderof the rubbery polymer particles (A) with extremely less impuritycontent can be obtained.

On the other hand, in a case of producing a dispersion (G) or a resincomposition in which the rubbery polymer particles (A) are dispersed inan organic solvent showing affinity with the rubbery polymerparticles(A) or a polymerizable organic compound (H) having the reactivefunctional group, the amount of the organic solvent (B) contained in theflocculate (F) obtained as described above by way of the flocculatingand the separating operation as described above is preferably 30% byweight or more and, more preferably, 35% by weight or more based on theentire weight of the flocculate (F). By the incorporation of the organicsolvent (B), dispersion to the organic solvent exhibiting the affinitywith the rubbery polymer particles (A) or the polymerizable organiccompound(H) having the reactive functional group to be carried outsuccessively can be practiced satisfactorily. In a case where thecontent of the organic solvent (B) is less than 30% by weight based onthe entire weight of the flocculate (F), it may sometimes result indisadvantages such as requiring a longer time for dispersion into theorganic solvent exhibiting the affinity with the rubbery polymerparticles (A) or to the polymerizable organic compound (H) having thereactivity group in the next step, or tending to leave irreversiblecoagulate and, as a result, dispersibility of the rubbery polymerparticles (A) into the polymerizable organic compound (H) tends to belowered remarkably.

The amount of the rubbery polymer particles (A) contained in the aqueousphase (E) separated and removed by the series of operations describedabove is 10% by weight or less, preferably, 5% by weight or less, andfurther preferably, 2% by weight or less based on the whole amount ofthe aqueous phase (E) and it is most preferred that the rubbery polymerparticles (A) are not substantially contained.

Then, re-dispersion of the obtained flocculate (F) into the organicsolvent exhibiting the affinity with the rubbery polymer particles (A)is to be described. By the operation, the dispersion (G) in which therefined rubbery polymer particles (A) in the flocculate (F) aredispersed in the organic solvent substantially in the state of primaryparticles can be obtained.

The amount of the organic solvent added may vary also depending on thekind of the rubbery polymer particles (A) and the kind and the amount ofthe organic solvent. The amount of the organic solvent added, ispreferably, from 40 to 1400 parts by weight and, more preferably, from200 to 1000 parts by weight based on 100 parts by weight of the rubberypolymer particles (A). When the amount of the organic solvent added isless than 40 parts by weight, the rubbery polymer particles (A) are lessdispersed uniformly in the organic solvent, lumps of the flocculate (F)of the rubbery polymer particles (A) tends to remain, or the viscosityincreases, making the handling difficult. When it exceeds 1400 parts byweight, it requires a great amount of energy and a large scale equipmentupon final evaporative removal of volatile ingredients by evaporation,which is not economical.

The organic solvent exhibiting the affinity with the rubbery polymerparticles (A) used herein is not particularly limited so long as it canre-disperse the rubbery polymer particles (A) and includes, for example,those exemplified for the organic solvent (B) used in the precedingstep, as well as aliphatic hydrocarbons such as hexane, heptane, octane,cyclohexane, ethylcyclohexane, and mixtures thereof. From a view pointof further ensuring the re-dispersibility of the loose flocculate, it ispreferred to use an organic solvent of a kind identical with that of theorganic solvent (B) used in the preceding step.

In the invention, the mixing operation of the flocculate (F) and theorganic solvent exhibiting the affinity with the rubbery polymerparticles (A) is not particularly limited but it can be carried out by ausual device having a mixing function.

Then, description is to be made for mixing of the dispersion (G) inwhich the thus obtained rubbery polymer particles (A) are dispersed withthe polymerizable organic compound (H) having the reactive functionalgroup and then removing volatile ingredients by evaporation. Thisoperation can provide a resin composition in which the rubbery polymerparticles (A) are dispersed in the polymerizable organic compound (H)having a reactive functional group and which scarcely contains anemulsifier and an electrolyte derived from the polymer particles.

The polymerizable organic compound (H) having the reactive functionalgroup used in the invention includes, for example, thermosetting resinssuch as epoxy resin, phenol resin, polyurethane resin and vinyl esterresin, radical polymerizable monomers such as aromatic vinyl compound,(meth)acrylic acid derivative, vinyl cyanate compound and maleimidecompound, and starting materials for aromatic polyesters such asdimethyl terephthalate and alkylene glycol. Among all, the process ofthe invention can be used particularly suitably to a thermosetting resintypically represented by the epoxy resin with which the rubbery polymerparticles described above are usually difficult to be blended.

The epoxy resin usable in the invention is not particularly limited solong as it is a compound having an epoxy group, and the epoxy resinusable in the invention is preferably an epoxy resin also referred to asa polyepoxide. The epoxy resin described above includes, for example;polyglycidyl ethers such as addition reaction products of polyhydricphenols such as bisphenol A, bisphenol F, biphenol, and phenols novolac,and epichlorohydrin; polyvalent glycidyl amine compounds derived frommonoamines and polyamines such as aniline, diamino benzene, aminophenol,phenylene diamine and diaminophenyl ether; cycloaliphatic epoxy resinshaving cycloaliphatic epoxy structures such as cyclohexyl epoxy;addition reaction products of polyhydric alcohols and epichlorhiderin;halogenated epoxy resins obtained by substituting a portion of hydrogenatoms thereof with halogen elements such a bromine; homopolymers orcopolymers obtained by polymerizing monomers including unsaturatedmonoepoxide such as aryl glycidyl ether. They may be used alone or as amixture of two or more of them. Various polyepoxides synthesized frompolyhydric phenols are described, for example, in U.S. Pat. No.4,431,782. Examples of the polyepoxides further include those describedin U.S. Pat. Nos. 3,804,735, 3,892,819, 3,948,698 and 4,014,771, and inEpoxy Resin Hand book (published from Nikkan Kogyo Shinbun Co. 1987).

The epoxy resins usable in the invention are as described above and theygenerally include those having an epoxy equivalent weight from 80 to2000. Such polyepoxides can be obtained by well-known methods and themethod of ten adopted usually includes, for example, reaction ofepihalohydrin in an excess amount to a polyhydric alcohol or polyhydricphenol under the presence of a base.

The epoxy resin usable in the invention may also contain, as a reactivediluent, a monoepoxide, for example, an aliphatic glycidyl ether such asbutyl glycidyl ether or phenyl glycidyl ether or cresyl glycidyl ether.As is generally known, mono-epoxide gives an effect on thestoichiometrical amount of the polyepoxide blend and it can be adjustedby the amount of a curing agent, or by other well-known method.

For the epoxy resin ingredient used in the invention, it is possible toincorporate a curing agent and/or curing promoter for the epoxygroup-containing compound described above and it is preferably a curingagent and/or curing promoter not substantially causing unexpected curingreaction with an epoxy resin under the condition of this productionprocess. For the curing agent and/or curing promoter, those satisfyingthe requirements described above can be selected from those described inEpoxy Resin Handbook described above and can be used.

For the method of removing by evaporation volatile ingredients such asan organic solvent (B), known methods are applicable. For example, theyinclude a method of charging the mixture in a vessel and removing byevaporation under heating at a reduced pressure, a method of putting adrying gas and the mixture in a counter current contact manner in avessel, a continuous method such as using a thin film evaporator, or amethod of using an extruder or a continuous mixing vessel provided withan evaporative removing mechanism. The conditions of temperature,necessary time, etc. upon removing the volatile ingredients byevaporation can be properly selected within the range not deterioratingthe quality of the resin composition. The amount of the volatileingredient remaining in the composition can be properly selected withinthe range not causing problem in accordance with the purpose of use ofthe composition.

According to the production process of the invention, an epoxy resincomposition in which the rubbery polymer particles (A) are uniformlydispersed in the polymerizable organic compound (H), for example, anepoxy resin ingredient and less impurities are included can be producedeasily and efficiently. The resin composition, for example, an epoxyresin composition obtained by the invention is usable generally tovarious application uses to which epoxy resins are used usually, forexample, as fiber or filler reinforcing composite materials useful forindustrial materials or sports goods, adhesives, paints, coatingmaterials, binders, and electric and electronic part materials such assemiconductor sealant, lamination plates for use in circuit substrates,and metal foils with resin, and cured molding product in which thedispersion state of the rubbery polymer particles (A) in the curedproduct is extremely stably and less impurities are included can beobtained.

As described above, according to a preferred embodiment of theinvention, a flocculate (F) from which impurities are remarkably removedcan be obtained continuously. This enables to continuously carry out theoperation of removing water and/or removing solvent from the mixture ofthe flocculate (F) and the aqueous phase (E), operation of dispersingthe flocculate (F) after the removing water and/or removing solventagain into an organic solvent, operation of mixing the dispersion (G) inwhich the flocculate (F) is dispersed with the polymerizable organiccompound (H) and operation of removing the volatile ingredient byevaporation from the mixture of the dispersion (G) and the polymerizableorganic compound (H), thereby enabling a continuous production methodsuitable to manufacture a few kinds of products in a large volume.

BEST MODE FOR PRACTICING THE INVENTIONS

The present invention is to be described specifically by way of examplesbut the invention is not restricted to such examples.

In the followings, the residual amount of impurities was analyzed basedon the amount of the emulsifier (anionic surfactant) and whole ions asthe index. Further, the dispersion state of the rubbery polymerparticles in the epoxy resin ingredient, that is, absence or presence ofcoagulation was judged by preparing a micro-thin slice from the obtainedcured product of the epoxy resin composition and then observing it undera transmission electron microscope (TEM).

Before description of examples, the analyzing and measuring method usedin the invention are to be explained below.

[1] Residual Amount of Emulsifier

For the residual amount of the emulsifier, the amount of the emulsifierremaining in the dispersion (G) before mixing with the epoxy resin (H)was measured by the following analysis method, which is digitalized as aratio (wt % ) assuming the whole amount of the emulsifier used in thepolymerization of the rubbery polymer particles (A) to be 100 wt % , andit was defined as the index.

[1-1] Pretreatment for Sample

In the following examples, a dispersion (G) in which the rubbery polymerparticles (A) before mixing with the epoxy resin (H) was sampled by 5ml, dried to solidness and charged together with 50 ml of ethanol into abeaker. After mixing the sample for 10 min, supernatants were used as asample for analysis by a methylene blue method to be described later.

[1-2] Methylene Blue Method

30 ml of water, 10 ml of an alkaline solution of sodium borate and 5 mlof a methylene blue solution (aqueous 0.025 wt % solution) were chargedin a separable flask. 20 ml of chloroform was added and shaken for 3 to5 min and then a chloroform layer was separated and removed. Theaddition/removal operation of chloroform was repeated till thechloroform layer was no more colored. Then, after adding 3 ml of dilutedsulfuric acid (aqueous solution of 2.9 wt %), 20 ml of chloroform and 2ml of sample prepared in [1-1] above, and shaking the mixture for 3 to 5min, the chloroform layer was measured for the residual amount of theemulsifier in the dispersion (G) before mixing the epoxy resin (A) byusing a spectrophotometer (spectrophotometer UV-2200, manufactured byShimadzu corporation), at an absorption of 650 nm wave length. Thealkaline solution of sodium borate was prepared by mixing 500 ml of 0.4wt % sodium hydroxide solution to 500 ml of an aqueous 1.9 wt % solutionof tetrasodium borate decahydrate.

[2] Residual Electrolyte (to Whole Ion)

Supernatants obtained in the same manner as in the sample pretreatmentwere measured as the sample for measuring electrical conductivity byusing an electro conductive mater (GM-117 manufactured by Kyotoelectronics manufacturing Co. LTD.) The ratio of the amounts of ionsremoved by a series of operations relative to the whole amount of theions derived from the latex of the rubbery polymer particles (A)(measured value for the rubbery polymer particles (A) dried tosolidness) was calculated as the total ion removal ratio.

[3] Ratio of Organic Solvent in Flocculate (F)

The ratio of the organic solvent in the flocculate (F) was calculated bymeasuring, the solid concentration (SC) and water content (WC) of theflocculate (F) by the following method and using the following formula.Ratio of organic solvent in flocculate (F)=100−(SC+WC)

[3-1] Measurement of Solid Concentration (SC) of Flocculate (F)

The flocculate (F) was sampled by a predetermined amount and dried in ahot blow drier, so that the solid concentration (SC) of the flocculate(F) was calculated based on the change of weight before and afterdrying.

[3-2] Measurement For Water Content (WC) in Flocculate (F)

After sampling the flocculate (F) by a predetermined amount anddispersing in a soluble solvent, the water content in the flocculate (F)was measured by a Karl Fisher method to calculate the water content (WC)to the whole flocculate (F).

[4] Determination of Rubbery Polymer Particles (A) Contained in AqueousPhase

A portion of an aqueous phase discharged by the method described inexamples and comparative examples was taken and dried the same at 120°C. sufficiently to obtain a residue, which was defined as the amount ofrubbery polymer particles (A) contained in the aqueous phase.

[5] Volatile Ingredient in Epoxy Resin Composition

In examples and comparative examples for obtaining the epoxy resincomposition, vacuum evaporation was continued till the volatileingredient to be defined below reached 5000 ppm. After preciselyweighing about 3 g of the epoxy resin composition, it was heated in ahot blow dryer at a setting temperature of 170° C. for 20 min and theweights before and after heating were measured, and the decrement of theweight was defined as a volatile ingredient (ppm) to calculate theweight ratio based on the weight before heating.

[6] Dispersed State of Rubbery Polymer Particles

[6-1] Preparation of Epoxy Resin Cured Product

51.9 g of an epoxy resin composition obtained in examples andcomparative examples and 13.1 g of diaminodiphenyl sulfone (manufacturedby Tokyo Kasei Co. LTD) were charged in a 100 ml beaker and mixed undermixing. The mixture was stood still in a vacuum dryer, heated at firstunder a nitrogen atmosphere to 130° C. and then the volatile ingredientwas removed by defoaming under a reduced pressure for 10 min. Afterporing the mixture into a molding die sized 100 mm×150 mm×3 mm, it washeated at 180° C. for 2 hours and further heated at 220° C. for 2 hoursfor curing to obtain a cured molding product.

[6-2] Observation For Dispersed State of Rubbery Polymer Particles UnderTransmission Electron Microscope

After a portion of the obtained molding product was cut out and, therubbery polymer particles (A) was dyed with osmium oxide, a slice wascut out and observed under a transmission electron microscope (JEM 1200EX type, manufactured by JEOL Ltd.) at a factor of 10000×, to judge thedispersion state of the rubbery polymer particles (A) in the epoxy resincured product.

PRODUCTION EXAMPLE 1

Production of Latex of Rubbery Polymer Particles (A)

200 parts by weight of water, 0.03 parts by weight of tripotassiumphosphate, 0.25 parts by weight of dihydrogen potassium phosphate, 0.002parts by weight of ethylene diamine tetraacetate, 0.001 parts by weightof ferrous sulfate and 1.5 parts by weight of sodium dodecyl benzenesulfonate were charged in a 100 L pressure proof polymerizing vessel,oxygen was removed by sufficient nitrogen substitution while mixing,then 75 parts by weight of butadiene and 25 parts by weight of styrenewere charged in a system and temperature was warmed to 45° C. 0.015parts by weight of paramentane hydroperoxide and, successively, 0.04parts by weight of sodium formaldehyde sulfoxylate were charged to startpolymerization. At 4 hours after starting polymerization, 0.01 parts byweight of paramenthane hydroperoxide, 0.0015 parts by weight ofethylene-diamine-tetra-acetate and 0.001 parts by weight of ferroussulfate were added. At 10 hours of polymerization, residual monomerswere removed by volatilization under a reduced pressure to terminatepolymerization. The polymerization conversion ratio was 98% and thevolume average particle size of the obtained styrene-butadiene rubberlatex was 0.1 μm.

Successively, 1300 g of the rubber latex (containing 420 g ofstyrene-butadiene rubber particles and containing 1.5% by weight ofsodium dodecyl benzene sulfonate as the emulsifier based on the solid ofthe rubber) and 440 g of refined water were charged in a 3 L glassvessel and stirred at 70° C. under a nitrogen substitution. After adding1.2 g of azobis isobutyronitrile (AIBN), a mixture of 54 g of styrene,72 g of methyl methacrylate, 36 g of acryronitrile and 18 g of glycidylmethacrylate were added continuously for 3 hours to carry out graftpolymerization. After the completion of the addition, stirring wasfurther applied for 2 hours and the reaction was terminated to obtain alatex of the rubbery polymer particles (A). The polymerizationconversion ratio was 99.5% . The obtained latex was used as it was.

EXAMPLE 1

To a 1-L vessel of an inner diameter 100 mm (equipped with an agitatorhaving flat 4-blade impeller in a size of 75 mm blade diameter) wereinstalled for 3 stages in the axial direction), 126 g methyl ethylketone (water solubility at 20° C. of 10% by weight) was charged, and126 g of the aqueous latex of rubbery polymer particles (A) obtained inProduction Example 1 was charged under mixing at 500 rpm. After mixinguniformly, 200 g of water was added at a feed rate of 80 g/min understirring at 500 rpm. After completion of feeding, the mixing was stoppedimmediately, a slurry comprising an aqueous phase containing floatingflocculate (F) and a portion of the organic solvent was obtained.

An aqueous phase was discharged by 348 g from a draining port at a lowerportion of the vessel while leaving the flocculate (F) containing aportion of the aqueous phase. The flocculate (F) containing the portionof the aqueous phase was 104 g and the ratio of the organic solvent was39% by weight based on the whole weight of the flocculate (F). Theflocculate (F) has a floating property and the flocculate (F) comprisedparticles having a particle size distribution. When a portion thereofwas sampled and put to image analysis, the number average particle sizewas about 5 mm. Further, the concentration of the rubbery polymerparticles (A) in the discharged aqueous phase was 0.23% by weight.

The obtained flocculate (F) was filtered through a filter with a suctionbottle and dried by using a box-type dryer under a nitrogen atmosphereat 40° C. for 12 hours to obtain refined rubbery polymer particles (A).A portion of the obtained flocculate was sampled, to which methyl ethylketone was added to prepare a dispersion (G) and the remainingemulsifier and the electrolyte were measured and, as a result, theremoval ratios were 95% and 90% respectively.

EXAMPLE 2

136 g of methyl ethyl ketone was added to 94 g of the flocculate (F)obtained in Example 1, mixed under the mixing condition at 500 rpm for30 min to obtain a dispersion (G) in which the rubbery polymer particles(A) were uniformly dispersed. The dispersion (G) was transferred to a1-L vessel of 100 mm inner diameter equipped with a jacket and aagitator (the agitator provided with an anchor impeller having a 90 mmblade diameter) and 92 g of an epoxy resin (Epicoat 828, manufactured byJapan Epoxy Resins Co.) was added and mixed uniformly. Then, the jackettemperature (warm water) was set to 60° C., and evaporation wascontinued by using a vacuum pump (oil-sealed rotary vacuum pump, TSW-150manufactured by Sato Vac. INC), till the volatile ingredient reached apredetermined concentration (5000 ppm) under vacuum, to obtain atransparent epoxy resin composition containing the rubbery polymerparticles (A). The time required for evaporation was 5 hours and 20 min.As a result of observing the dispersed state of the rubbery polymerparticles (A) in the cured product obtained from the epoxy resincomposition, they were uniformly dispersed with no coagulation.

EXAMPLE 3

To a 1-L vessel of 100 mm inner diameter equipped with an agitator (theagitator with Pfaudler impeller having a 56 mm blade diameter), 144 g ofmethyl ethyl ketone was charged, and 144 g of an aqueous latex ofrubbery polymer particles (A) obtained in Production Example 1 wascharged under mixing at 400 rpm and mixed uniformly. After introducing207 g of water moderately from the draining port at a lower port of thevessel in a state of stopping the mixing, mixing was effected for 2 minunder mixing at 400 rpm. After completion of the stirring, a slurrycomprising an aqueous phase containing the flocculate (floatingproperty) and the organic solvent was obtained. An aqueous phase wasdischarged by 373 g from a draining port at a lower port of the vesselwhile leaving the flocculate (F) containing a portion of the aqueousphase. The flocculate (F) containing the portion of the aqueous phasewas 122 g and the ratio of the organic solvent was 45% by weight basedon the whole weight of the flocculate. The number average particle sizeof the flocculate was about 5 mm. Further, the concentration of theingredient of the rubbery polymer particles(A) in the discharged aqueousphase was 0.28% by weight. Subsequently, by the same procedures as thosein Example 1, polymer particles were obtained. A portion of the obtainedflocculate was sampled, to which methyl ethyl ketone was added toprepare a dispersion (G) and remaining emulsifier and electrolyte weremeasured and, as a result, the removal ratios were 92% and85%respectively.

EXAMPLE 4

173 g of methyl ethyl ketone was added to 122 g of the flocculateobtained in Example 3, mixed under the mixing condition at 400 rpm for30 min to obtain a dispersion in which the rubbery polymer particles (A)were uniformly dispersed. The dispersion was transferred to a 1-L vesselof 100 mm inner diameter equipped with a jacket and an agitator (theagitator provided with an anchor impeller having 90 mm blade diameter)and 116 g of an epoxy resin (Epicoat 828 manufactured by Japan EpoxyResins Co.) was added and mixed uniformly. Then, the jacket temperature(warm water) was set to 60° C., and evaporation was continued by using avacuum pump till the volatile ingredient reached a predeterminedconcentration (5000 ppm) under vacuum, to obtain a transparent epoxyresin composition containing the rubbery polymer particles (A). The timerequired for evaporation was 5 hours and 20 min. As a result ofobserving the dispersed state of the rubbery polymer particles (A) inthe cured product obtained from the epoxy resin composition, they wereuniformly dispersed with no coagulation.

COMPARATIVE EXAMPLE 1

Residual Amount of Impurities in the Coagulated Particles by Addition ofCoagulant

To an 1-liter volume vessel of 100 mm inner diameter equipped with anagitator (the agitator with flat 4-blade impeller having 75 mm bladediameter were installed for 3 stages in the axial direction), 500 g ofthe aqueous latex of the rubbery polymer particles (A) of ProductionExample 1 was charged and, under 400 rpm, 13 g of an 35 wt % watersolution of calcium chloride as a coagulant was charged to form acoagulate. The coagulate was filtered by a filter with a suction bottle.After adding 500 g of water to the coagulate on the filter for washing,the coagulate was dried at 40° C. for 12 hours by using a box-type drierto obtain rubbery polymer particles (A). When the coagulate afterwashing was separately sampled by 10 g and mixed with 100 g of methylethyl ketone by using a homo mixer, the rubbery polymer particles (A)were not completely dispersed in the methyl ethyl ketone but partiallyhaving the shape of coagulated particles as they were. Accordingly, whenas a sample pretreatment, the coagulate after washing was sampled by 10g and mixed with methanol to extract impurities to bring a sample of 50ml and, when remaining emulsifier and electrolyte were measured by usingthe same, the removal ratio was 22% and 15% , respectively.

COMPARATIVE EXAMPLE 2

Dispersibility of Coagulated Particles into Resin Composition byAddition of Coagulant.

50 g of the rubbery polymer particle(A) after drying obtained inComparative Example 1 was transferred to a 1-L vessel of 100 mm innerdiameter equipped with a jacket and an agitator (the agitator providedwith an anchor blade having 90 mm blade diameter) and 135 g of an epoxyresin (Epicoat 828 manufactured by Japan Epoxy Resins Co.) was added andmixed uniformly. Then, the jacket temperature (warm water) was set to60° C., and evaporation was continued by using a vacuum pump (oil-sealedrotary vacuum pump, TSW-150 manufactured by Sato VAC. Inc), till thevolatile ingredient reached a predetermined concentration (5000 ppm)under vacuum, to obtain a transparent epoxy resin composition containingthe rubbery polymer particles (A). The time required for evaporation was5 hours and 20 min. As a result of observing the dispersed state of therubbery polymer particles (A) in the cured product obtained from theepoxy resin composition, it was confirmed that the rubbery polymerparticles (A) were coagulated) across the whole cured product.

COMPARATIVE EXAMPLE 3

Dispersibility of Polymer Particles in Resin Composition in a Case ofDirectly Mixing Latex

To a 1-L volume vessel of 100 mm inner diameter equipped with a jacketand a agitator(the agitator provided with an anchor blade having a 90 mmblade diameter), 150 g of the aqueous latex of the rubbery polymerparticles (A) of Production Example 1 was charged, 121 g of an epoxyresin (Epicoat 828 manufactured by Japan Epoxy Resins Co.) was added andmixed uniformly. Then, the jacket temperature (warm water) was set to60° C., and evaporation was continued by using a vacuum pump, till thevolatile ingredient reached a predetermined concentration (5000 ppm)under vacuum, to obtain a epoxy resin composition containing the rubberypolymer particles (A). Since a great amount of water content remained,it took 11 hours and 40 min for the removal of volatile ingredients byevaporation. As a result of observing the dispersion state of therubbery polymer particles (A) in the cured product obtained from theepoxy resin composition, it was confirmed that the rubbery polymerparticles (A) were coagulated across the whole cured product.

COMPARATIVE EXAMPLE 4

Removal of Impurities in Latex Using Organic Solvent

To an 1-liter volume vessel of 100 mm inner diameter equipped with anagitator(the agitator with flat 4-blade impeller having a 75 mm bladediameter were installed for 3 stages in the axial direction), 500 g ofmethyl ethyl ketone was charged, and 126 g of the aqueous latex of therubbery polymer particles (A) obtained in Production Example 1 wascharged under mixing at 100 rpm. After mixing uniformly, they were stoodstill for 16 hours to obtain a liquid mixture in a state separated intotwo phases of 590 g of an upper phase (water containing methyl ethylketone) and 36 g of a lower phase (aqueous phase). As a result ofsampling the upper phase and measuring remaining emulsifier andelectrolyte, the removal ratio was 18% and 14% respectively.

COMPARATIVE EXAMPLE 5

Dispersibility of Polymer Particles in Resin Composition in a Case ofUsing Organic Solvent

To a 1-L vessel of 100 mm inner diameter equipped with jacket andagitator(the agitator provided with an anchor impeller having a 90 mmblade diameter), 590 g of the organic phase (upper phase, methyl ethylketone phase) obtained in Comparative Example 4 was transferred and 97 gof an epoxy resin (Epicoat 828 manufactured by Japan Epoxy Resins Co.Ltd.) was added and mixed uniformly. Then, the jacket temperature (warmwater) was set to 60° C., and evaporation was continued by using avacuum pump, till the volatile ingredient reached a predeterminedconcentration (5000 ppm) under vacuum, to obtain a transparent epoxyresin composition containing the rubbery polymer particles (A). The timerequired for evaporation was 8 hours and 50 min. As a result ofobserving the dispersed state of the rubbery polymer particles (A) inthe cured product obtained from the epoxy resin composition, it wasconfirmed that the rubbery polymer particles were coagulated in aportion of the cured product.

COMPARATIVE EXAMPLE 6

Removal of Impurities in Latex Using Organic Solvent and Electrolyte

To an 1-liter volume vessel of 100 mm inner diameter equipped with anagitator (the agitator with flat 4-blade impeller having a 75 mm bladediameter were installed for 3 stages in the axial direction) kept at 25°C., 340 g of methyl ethyl ketone was added, and 252 g of the aqueouslatex of the rubbery polymer particles (A) of Production Example 1 wascharged under mixing. After mixing uniformly, 126 g of water wascharged, 30 g of 5% aqueous solution of sodium sulfate was added undermixing, the organic phase and the aqueous phase were separated and thenthe aqueous phase was discharged. As a result of sampling the obtainedaqueous phase and measuring the remaining emulsifier and theelectrolyte, the removal ratio was 60% and 35% respectively.

Further, after mixing the organic phase with 204 g of an epoxy resin,the volatile ingredient was removed by evaporation under vacuum till itreached a predetermined concentration of 5000 ppm, to obtain an epoxyresin composition containing rubbery polymer particles (A). The timerequired for evaporation was 9 hours and 10 min. As a result ofobserving the dispersed state of the rubbery polymer particles in thecured product obtained from the epoxy resin composition, they wereuniformly dispersed with no coagulation.

EXAMPLE 5

Turbine blades each of 50 mm blade diameter were installed by fourstages to a vertical 1-L mixing vessel with 70 mm vessel diameter and350 mm height and mixing was effected at 450 rpm. Successively, amixture (C) formed by mixing the aqueous latex of the rubbery polymerparticles (A) of Production Example 1 and methyl ethyl ketone (B) eachin an equal weight was supplied at a position 50 mm above the bottom ofthe mixing vessel at a feed rate of 128 ml/min. Simultaneously, water(D) was supplied from another supply port disposed at an identicalheight above the bottom of the stirring vessel at a feed rate of 92ml/min. The mixing ratio for the aqueous latex of the rubbery polymerparticles (A), methyl ethyl ketone (B) and water (D) was 100 parts byweight, 100 parts by weight and 160 parts by weight, and the meanresidence time in the mixing vessel was 4.5 min. The height from thebottom to the liquid surface of the mixing vessel was 300 mm. A slurrycomprising the flocculate (F) and the aqueous phase (E) was collected byoverflow at a position for the liquid surface in the upper portion ofthe mixing vessel. Operation was carried out for 10 min to flocculate580 g of the aqueous latex of the rubbery polymer particles (A). Liquidwas removed from the obtained slurry, and methyl ethyl ketone was addedto the flocculate (F) to prepare a dispersion (G), and the remainingemulsifier and electrolyte were measured. Removal ratio was 95% and 90%respectively, and the quality was good.

EXAMPLE 6

136 g of methyl ethyl ketone was added to 94 g of the flocculate (F)obtained in Example 5, and mixed for 30 min under the mixing conditionat 500 rpm to obtain a dispersion (G) in which the rubbery polymerparticles (A) were uniformly dispersed. The dispersion was transferredto a 1-L vessel of 100 mm inner diameter with a jacket and anagitator(the agitator provided with an anchor blade having a 90 mm bladediameter) and 92 g of an epoxy resin (Epicoat 828 manufactured by JapanEpoxy Resins Co. LTD.) was added and mixed uniformly. Then, the jackettemperature (warm water) was set to 60° C., and evaporation wascontinued by using a vacuum pump (oil-sealed rotary vacuum pump, TSW-150manufactured by Sato Vac. Inc.), till the volatile ingredient reached apredetermined concentration (5000 ppm) under vacuum, to obtain atransparent epoxy resin composition containing the rubbery polymerparticles (A). As a result of measuring the dispersed state of therubbery polymer particles (A) in the cured product obtained from theepoxy resin composition, they were uniformly dispersed with noflocculation.

EXAMPLE 7

The same procedures as those in Example 5 were carried out except forchanging the amount of water (D) supplied to 106 ml/min, 184 parts byweight. The mean residence time in the vessel was 4.3 min. A dispersion(G) was prepared by adding methyl ethyl ketone to a portion of theflocculate (F) collected by overflow from the position at the liquidsurface in the upper portion of the mixing vessel and the remainingemulsifier and electrolyte were measured. The removal ratio was 90% and80% respectively and the quality was good.

EXAMPLE 8

The same procedures as those in Example 6 were carried out except forusing the flocculate (F) obtained in Example 7 to obtain an epoxy resincomposition containing rubbery polymer particles (A). As a result ofobserving the dispersed state of the rubbery polymer particles obtainedfrom the epoxy resin composition, the rubbery polymer particles wereuniformly dispersed without coagulation.

EXAMPLE 9

The flocculate obtained in Example 7 was dried by a dryer at 70° C. for2 hours. As a result, a dry powder with a volume average particle sizeof about 800 μm was obtained.

EXAMPLE 10

To a 1-L vessel of 100 mm inner diameter equipped with an agitator (theagitator with pfaudller impeller having a 56 mm blade diameter wereinstalled), 144 g of methyl ethyl ketone was charged, and 144 g of anaqueous latex of rubbery polymer particles (A) obtained in ProductionExample 1 was charged under mixing at 400 rpm, and mixed uniformly. Theliquid volume was 530 ml. After introducing 207 g of water slowly fromthe draining port in a lower part of the vessel in a state of stoppingthe mixing, mixing was effected for 4.5 min under mixing at 400 rpm.After completing the mixing, a slurry comprising a floating flocculate(F) and an aqueous phase (E) containing the organic solvent wasobtained. It took about 12 min to obtain the slurry from the start ofsupplying the raw material.

A portion of the obtained flocculate was sampled and methyl ethyl ketonewas added to prepare a dispersion, and the remaining emulsifier andelectrolyte were measured. As a result, the removal ratio was 92% and85% respectively, showing no significant difference in view of thequality, compared with Example 5 in which flocculation was carried outby continuous operation.

EXAMPLE 11

The same procedures as those in Example 6 were carried out except forusing the flocculate obtained in Example 10 to obtain an epoxy resincomposition containing rubbery polymer particles (A). As a result ofobserving the dispersed state of the rubbery polymer particles (A)obtained from the epoxy resin composition, the rubbery polymer particles(A) were uniformly dispersed without coagulation, to provide qualitycomparable with that of Example 6 or 8.

INDUSTRIAL APPLICABILITY

According to the process of the invention, refined rubbery polymerparticles can be produced by an easy method of obtaining a looseflocculate from rubbery polymer particles obtained in a state of theaqueous latex in the presence of the organic solvent without using acoagulant, and efficiently discharging impurities to the side of theaqueous phase. Further, since the flocculate can be continuouslycollected by mixing and contacting a mixture of an aqueous latex and anorganic solvent and water continuously, the production efficiently ishigh and the cost of the equipment can be suppressed.

Further, since the obtained loose flocculate has reversibility, when itis re-dispersed in the organic solvent and then mixed with thepolymerizable organic compound or the like, rubbery polymer particlescan be uniformly mixed and dispersed in the polymerizable compound. Thatis, a resin composition with remarkably decreased impurities such as theemulsifier and electrolyte derived from the polymer particles can beproduced.

1. A process for producing refined rubbery polymer particles (A)comprising: bringing water (D) into contact with a mixture (C) obtainedby mixing an aqueous latex of the rubbery polymer particles (A) with anorganic solvent (B) exhibiting partial solubility to water; therebyforming a flocculate (F) of the rubbery polymer particles (A) containingthe organic solvent (B) in an aqueous phase (E); and then separating theflocculate (F).
 2. The process according to claim 1, wherein water (D)is continuously mixed and brought into contact with mixture (C).
 3. Theprocess according to claim 2, wherein the mixture (C) and the water (D)are supplied from the bottom of the mixing device and the mixture of theflocculate (F) and the aqueous phase (E) is recovered from an upper partof the mixing device.
 4. A process for producing refined rubbery polymerparticles (A), comprising: removing water and/or removing solvent fromthe flocculate (F) of the refined rubbery polymer particles (A) obtainedby the process according to any one of the claims 1 to 3, followed bydrying.
 5. A process for producing a dispersion (G), comprising: addingan organic solvent exhibiting an affinity with the rubbery polymerparticles (A) to the flocculate (F) of refined rubbery polymer particles(A) obtained by the production process according to any one of claims 1to 3, thereby obtaining the dispersion (G) in which the rubbery polymerparticles (A) are dispersed in the organic solvent.
 6. A process forproducing a resin composition comprising rubbery polymer particles (A)dispersed in a polymerizable organic compound (H) having a reactivefunctional group, comprising: mixing the dispersion (G) obtained by theproduction process according to claim 5 and the polyrnerizable organiccompound (H) and then removing the volatile ingredient by evaporation.7. A process for producing a resin composition comprising rubberypolymer particles (A) dispersed in a polymerizable organic compound (H)having a reactive functional group, comprising: mixing the flocculate(F) obtained by the process according to any one of claims 1 to 3 andthe polymerizable organic compound (H) and then removing the volatileingredient by evaporation.
 8. The process for a resin compositionaccording to claim 6, wherein the polymerizable organic compound (H)having the reactive functional group is an epoxy resin.
 9. The processaccording to any one of claims 1 to 3, wherein the solubility to waterat 20 C of the organic solvent (B) exhibiting a partial solubility towater is 5% by weight or more and 40% by weight or less.
 10. The processaccording to any one of claims 1 to 3, wherein the amount of water (D)to be brought into contact with the mixture (C) obtained by mixing theaqueous latex of the rubbery polymer particles (A) with the organicsolvent (B) exhibiting the partial solubility to water is 40 parts byweight or more and 350 parts by weight or less based on 100 parts byweight of the organic solvent (B).
 11. The process according to any oneof claims 1 to 3, wherein the ratio of the organic solvent (B)exhibiting the partial solubility to water contained in the flocculate(F) is 30% by weight or more based on the entire weight of theflocculate (F).
 12. The process according to any one of claims 1 to 3,wherein the rubbery polymer particles (A) comprise a polymer having atwo or more multi-layered structure and contain at least one layer ofcross-linked rubbery polymer layer.
 13. The process according to any oneof claims 1 to 3, wherein the rubbery polymer particles (A) comprise agraft copolymer having 5 to 60% by weight of a shell layer (A-2)obtained by polymerizing at least one vinyl polymerizable monomerselected from (meth)acrylate ester, aromatic vinyl, vinyl cyanate,unsaturated acid derivative, (meth)acrylamide derivative and maleimidederivative in the presence of 40 to 95% by weight of a rubber particlecore (A-1) comprising an elastomeric material constituted with 50 to100% by weight of at least one monomer selected from diene monomer and(meth)acrylate ester monomer, and 0 to 50% by weight of othercopolymerizable vinyl monomer, a polysiloxane elastomeric material or amixture thereof.
 14. The process according to claim 13, wherein theshell layer (A-2) of the rubbery polymer particles (A) has at least onereactive functional group selected from the group consisting of epoxygroup, carboxylic group, hydroxylic group and carbon-to-carbon doublebond.
 15. The process for a resin composition according to claim 7,wherein the polymerizable organic compound (H) having the reactivefunctional group is an epoxy resin.